PURPOSE: The purpose of this study is to describe the results of endonasal endoscopic nasolacrimal duct dissection (EE-NLDD); a surgical technique used for the treatment of primary nasolacrimal duct obstruction (NLDO). MATERIALS AND METHODS: Before the operation, the patency of the nasolacrimal duct (NLD) was evaluated through irrigation and probing. The EE-NLDD surgical procedure involved the removal of the bony structure covering the NLD. The NLD mucosa was dissected and marsupialized with nasal mucosa, creating a mucosa-covered ostium. The bone surrounding the lacrimal fossa and lacrimal sac mucosa was preserved throughout procedure. The postoperative anatomical and functional outcomes were evaluated through irrigation, endonasal endoscopic fluorescein dye test, and subjective descriptions of the patients. STUDY DESIGN: This is a retrospective chart review study which included all patients with primary NLDO treated with EE-NLDD surgical technique from February 2012 to July 2016 in Taipei Medical University Shuang Ho Hospital by a single surgeon (YD, Shen). RESULTS: The mean follow-up time for the 39 patients (43 eyes) was 14.7 months (range: 0.5-46 months). Anatomical patency was achieved in all patients. Under endonasal endoscopy, fluorescein dye was observed at the internal orifice after the dye was instilled into the conjunctival sac in all patients. The complete resolution of the epiphora was reported in 36 patients (39 eyes) and two patients (2 eyes) exhibited an improvement of the epiphora after surgery. However, one patient (2 eyes) reported persistent bilateral epiphora without improvement even under solid evidence of anatomical patency. No major complications were noted intraoperatively or postoperatively. CONCLUSIONS: The results suggested that the EE-NLDD is a safe and effective procedure and has a success rate comparable with that of conventional endonasal dacryocystorhinostomy.